Apparatus for decoking a delayed coker

ABSTRACT

Coke is removed from the delayed coker or container by hydraulically cutting a substantial portion or all of it in a substantially vertical direction with water jet streams emanating from nozzles operatively mounted and coupled to a central drill stem which is provided with water under pressure and which is capable of rotation and vertical movement within the container. The coupling is by mechanical and hydraulic linking means permitting the movement of the nozzles in a radial direction from the axis of the central drill stem. After the cutting of the pilot hole with a conventional cutting head designed for that purpose, a substantial portion or all of the remainder of the coke in the container is removed by hydraulically cutting the coke in a substantially vertical direction by directing the water jet streams from the nozzles in a substantially vertical and downward direction against the horizontal surface of the coke in a series of radial incremental distances (which may be variable) substantially circumferentially across the surface of the coke. After each radial incremental cut, the drill stem is raised in the container, the nozzles are extended radially and the nozzles are then moved vertically from the top of the coke to the bottom thereof by lowering the drill stem as the coke is removed by the action of the water, thereby forming a varying, increasing diameter, cylindrical void in the container through which passes the remainder of the coke that is removed in this manner.

United States Patent [191 Novy 1 1 APPARATUS FOR DECOKING A DELAYEDCOKER [75] Inventor:

[73] Assignee.- Great Lakes Carbon Corporation, New York, N.Y.

22 Filed: Apr. 24, 1974 21 Appl. No.: 463,581

Related U.S. Application Data [62] Division of Ser. No. 238.304. March27. 1972, Pat.

Anton R. Novy. Johnson City, Tenn.

[52] U.S. Cl. 239/565; 239/587; 201/2; 202/241; 134/24; 134/39; 134/168R [51] Int. Cl ClOc 3/18; B05b 1/14; B05b 15/08 [58] Field of Search239/227, 243-245, 239/565, 587, 588; 201/2; 202/241; 134/24,

8, 39,167 R, 168 R; 15/104 1 C;208/48, 131

Primary Examiner-Robert S. Ward, Jr. Attorney. Agent, or FirmWallace F.Neyerlin 1 Apr. 29, 1975 [57] ABSTRACT Coke is removed from the delayedcoker or container by hydraulically cutting a substantial portion or allof it in a substantially vertical direction with water jet streamsemanating from nozzles operatively mounted and coupled to a centraldrill stem which is provided with water under pressure and which iscapable of rotation and vertical movement within the container. Thecoupling is by mechanical and hydraulic linking means permitting themovement of the nozzles in a radial direction from the axis of thecentral drill stern. After the cutting of the pilot hole with aconventional cutting head designed for that purpose, a substantialportion or all of the remainder of the coke in the container is removedby hydraulically cutting the coke in a substantially vertical directionby directing the water jet streams from the nozzles in a substantiallyvertical and downward direction against the horizontal surface of thecoke in a series of radial incremental distances (which may be variable)substantially circumferentially across the surface of the coke. Aftereach radial incremental cut, the drill stem is raised in the container,the nozzles are extended radially and the nozzles are then movedvertically from the top of the coke to the bottom thereof by loweringthe drill stem as the coke is removed by the action of the water,thereby forming a varying. increasing diameter, cylindrical void in thecontainer through which passes the remainder of the coke that is removedin this manner.

3 Claims. 12 Drawing Figures 1 APPARATUS FOR DECOKING A DELAYED COKERThis application is a Divisional application of Application Ser. No.238,304 filed Mar. 27, I972 now Pat. No. 3,836,434.

BACKGROUND OF THE INVENTION Field of the Invention and Description ofthe Prior Art This invention relates to a process and apparatus forremoving coke which has been formed in coke drums or containers by adelayed coking process.

The production of coke by the delayed coking process involves theheating of a petroleum residual oil or pitch (or coal tar pitch) to ahigh temperature, and per mitting the residual heat of the coker feed toconvert it to coke in a generally cylindrically shaped drum or containerfrom which the coke is removed by mechanical and hydraulic decokingtools. In the removal of the coke, the coke is initially cooled withsteam, followed by a mixture of steam and water until the coketemperature is below 212F, after which the coke and drum are floodedwith water to complete the cooling.

After the water is drained from the drum, a central pilot is then boredin the coke by lowering a drill stem which is provided with aconventional cutting head designed for boring the pilot hole with highpressure water. The initial cutting head is replaced by another cuttinghead and the drill stem is then inserted into and along the axis of thepilot hole, High pressure water jetting from the second cutting headbreaks up and cuts the coke from the drum by being directed at it in aseries of horizontal cutting intervals going progressively from the topto the bottom of the coke in the drum, during which the coke is removedfrom the bottom of the drum.

The solid coke product removed from the drum is typically referred to asraw coke because it still contains a substantial percentage of organicvolatile matter. The raw coke is then typically calcined to enhance itsusefulness during which it is heated to a substantially highertemperature (e.g. about l,300C) than it was subjected to in the delayedcoking drum and in which step its volatile matter content issubstantially reduced.

It is desirable that coke to be calcined have a minimum of fines and thelowest possible volatile matter. The fines create dusting problems inhandling, storage and calcination of the coke and are of lower valuethan lump coke, and the volatile matter content is usually largelyresponsible for and inversely proportional to the calcined particledensity of the coke. (A high particle density is generally desired bythe ultimate user of the coke). In contrast, the coke producer is mainlyinterested in decoking the drum as rapidly as possible. Since a *soft"(high volatile) coke is easiest to cut, the coke producer is reluctantto reduce the volatile content to the levels desired by the calcinersand ultimate users of the coke.

As indicated, at the present time the most commonly used decoking toolsconsist of two hydraulic cutting heads used in succession. (In any case,the decoking tool used is operatively connected to a central drill stemwhich can be lowered through the coking drum and by means of which thedecoking tool is supplied with water under pressure). The first headpossesses a series of nozzles which are placed or directed in anessentially vertical manner and is used to cut the initial or pilot holein the bed of coke. This head is then removed from the drill stern andreplaced by a cutting head which uses two or four nozzles which directwater jets in an essentially horizontal manner. The drill stem is thenprogressively lowered in the drum a number of cutting intervals, duringwhich intervals approximately horizontal layers of coke are cut from thecoke bed.

It is apparent that this technique of coke removal is relativelyinefficient since substantially every lump of coke dislodged from thebed must be washed over the edge of the coke bed into the pilot hole.The nozzle cutting stream operates in the opposite direction tending todrive the dislodged lumps away from the pilot hole toward the wall ofthe coking drum. This also results in an undesirable grinding actionwhich results in an excess of fines.

At the present time, also, a modified cutter head using nozzles placedat a 20 to 30 angle above horizontal has been described and is beingconsidered as a replacement for the conventional head. This should improve the operation of the nozzle by providing a downward slopingsurface toward the pilot hole on the coke bed to accelerate the movementof the lumps toward the discharge, but also suffers from otherdisadvantages, which will become apparent hereinafter, as compared tothe decoking technique of the present inven tion.

A tend in the delayed coking industry is toward larger diameter drums.The largest in operation today are 26 feet in diameter. Drums up to 40feet in diameter are being discussed. As the diameter increases. theeffectiveness of the cutting stream is reduced when employing cokeremoval techniques of current practice. This loss is presently beingovercome by the use of high pressures and larger water flows. Thefollowing table, based upon data contained in a paper presented at thePetroleum Mechanical Engineering and Pressure Vessels and PipingConference, Denver, Colorado, U.S.A. Sept. 13-17, I970, by R..Iagodz'mski', R. W. Piazza; and R. L. Bodin and entitled HydraulicDecoking- Design Versus Cutting Time" shows typical flows and pressuresused today in drums of different sizes:

Drum Diameter, feet Pressure, psi Water Flow Gallons per Minute (GPM) 19to 22 2200 A 2500 750 800 23 to 24 2500 3000 800 I000 SUMMARY OF THEINVENTION It is an object of the present invention to provide a processand apparatus for decoking a delayed coker wherein there is no reallimit imposed to the coking drum diameter by the decoking tool; whereinsignificantly fewer fines are produced since little or no grinding ofdislodged lumps occurs; and wherein signifi cantly lower pressures andwater volumes are required to achieve the cutting rates attained bypresent cutting systems, or wherein, for the same pressures and volumes,significantly shorter decoking times are achieved.

It is another object of the present invention to carry out the decokingof a delayed coker by means capable of providing rapid cutting ofrelatively hard, low volatile coke because the cutting operation tendsto auto matically compensate for the hardness of the coke, For any givenrate of downward motion ofthe cutting head, the distance between thenozzles and the cutting surface will tend to become relatively large insoft coke. As the coke becomes harder and because of the fea tures ofthetechnique and decoking tool of the present invention, this distance willbecome shorter and thus the greater cutting energy close to the nozzlescan be brought to bear on the coke.

The decoking tool of the present invention is just as efficient in a 40foot diameter drum as in a 20 foot drum. In addition, its efficiency issignificantly greater than designs of the prior art because the decokingis accomplished with significantly lower water pressures and volumessince, as aforesaid, the cutting can be done at a short, relativelyconstant distance from the nozzles and in any event, at a more constantdistance than when employing decoking techniques of the prior art. Theoperation involves a minimum of grinding and a maximum of cutting andthe dislodged lumps are dropped directly into the pilot or central holerather than being driven toward the wall of the coking drumv Otherobjects, and coincident advantages, and a complete understanding of theinvention will be apparem to those skilled in the art after a study ofthe drawings, and a reading of the specification and claims.

The tool or apparatus used in the technique of the present inventionconsists of or includes, in combination:

Water nozzles capable of directing water in jet streams in asubstantially vertical and downward direction against the coke;

a central drill stem, which can be provided with water under pressure,capable of rotation and vertical movement within the coking container ordrum, to which stem the jet nozzles are operatively mounted and coupled;and

mechanical and hydraulic linking means between the water nozzles and thecentral drill stem for radially extending the cutting action of the jetstreams while simultaneously maintaining the jet nozzles in the samesubstantially vertical direction, thus enabling a series ofsubstantially cylindrical and vertical, hydraulic cuttings, and thusalso enabling each subsequent cylinder hydraulic cutting in the seriesto enlarge the diameter of the central hole in the container by thetotal radial movement of the linking means between each respectivecutting in the series.

The inclusion of specific apparatus parts (described hereinafter) whichactuate the linking means, and which thus cause the enlarged diametercutting action of the jet streams, comprise another novel apparatuscombination of the present invention.

The sub-combination of water nozzles and linking means is alsoconsidered a novel and patentable embodiment of the present invention.

Because of the foregoing features of the apparatus of the presentinvention, the nozzles thus are also mounted on the drill stem by anarrangement which is capable of maintaining a constant nozzle distancefrom the surface of the coke while each vertical hole of progressivelygreater diameter is serially cut.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing objects are achievableby removing the coke from the drum in a manner as illustratedschematically in FIGS. 26. Apparatus which makes possible the cokeremoval as indicated in these figures is illustrated primarily in FIGS.7-12 and also in FIG. 1 which merely shows schematically some equipmentfeatures of the present invention.

FIG. 7 is a front view of the mechanical and hydraulic valve cutterassembly and linking means mechanism which can be employed in thepresent invention and which make possible coke removal techniques suchas have just been briefly described.

FIG. Sis a top plan view of the apparatus taken along line 8-8 of FIG.7.

FIG. 9 is a side or end view of the apparatus taken along line 99 ofFIG. 7 (with the nozzle arms retracted).

FIG 10 is a top plan view (with the nozzle arms extended, or inhorizontal position) of an alternate form of nozzle arrangement whichcan be employed in the present invention to carry out the variationillustrated in FIG. 5.

FIG. 11 is a front view of the nozzle arrangement of FIG. 10.

FIG. 12 is a view similar to FIG. 11 but wherein the linkage means tothe nozzles are in the extended posi' tion, thereby rotating the nozzlesinto substantially horizontal direction so as to carry out the processvariation of FIG. 5.

DETAILED DESCRIPTION OF THE DRAWINGS In FIG. I there is schematicallyshown a typical environment or construction in which the device and/orprocess of the present invention are employed. The coking container 3 issurrounded by a construction of framework I0, similar to an oil wellderrick, which is suitable for lowering drill stem 7 entirely throughthe container. This lowering can be accomplished through the use of ahydraulic or mechanical motor 8 suitably connected to the framework bysupport brackets 9. In other words, conventional equipment or means maybe employed to raise and lower the drill stem, to rotate it at asuitable speed, and to supply water thereto.

In FIGS. 2-6 various coke removal steps of the process of the presentinvention are illustrated schematically, it being appreciated that thesteps illustrated are representative, and that more steps may beemployed than are actually illustrated.

In FIG. 2, a substantially vertical and central pilot hole 1 has alreadybeen cut through the entire height of the coke 2 in the container 3according to a procedure standard in the art. Container or drum 3 isabout feet in length between upper opening 4 and lower opening 5. Theopening 4 of the drum at the top is about 3 feet in diameter and theopening 5 of the drum at the bottom is about 5-6 feet in diameter. Theinitial distance between top opening 4 and the top surface 6 of the cokein the container, which is referred to as outage," is generally at leastl or more feet. In cut ting the central pilot hole, a drill stem 7,which typically possesses a diameter between about 4 and 6 inches, waslowered through the top opening of the container after an initialcutting nozzle assembly had been coupled to same. The drill stem wasprovided with water under pressure and this water was directed againstthe top surface of the coke through the cutting nozzle assembly. Theinitial cutter which was employed to cut the pilot hole through the cokeis about l5l8 inches in diameter and results in a pilot hole I about 30inches in diameter. (It should be appreciated that the openings andcontainer dimensions, etc. of the figures are not scale drawings but arefor purposes of explanation only). The drill stem, driven eitherhydraulically or mechanically, was caused to rotate slowly such as at aspeed of 2 to 4 revolutions per minute. The drill stem is typicallyabout 100 feet long, or about feet longer than the container, in orderto provide for connection to the drive means above the container and sothat its lower end may extend to the bottom of the container. The drillstem is periodically lowered as the coke surface, against which the jetstreams from the nozzles are directed, becomes progressively lower,until eventually the central pilot hole is cut through the entire heightof the coke in the container. The coke removed from the container istypically cut either into a dewatering pit or directly into a railroadcar for shipment to subsequent place of usage. What has been describedthus far is a standard step or procedure in the art.

After the cutting of the pilot hole, the drill stem is raised until theinitial cutter attached to same is above the top opening of thecontainer or drum so that the initial cutter can be removed and adifferent jet nozzle assembly can be attached in its place. This changeof cutting heads is conveniently accomplished through the use of a steelcoupling or quick release joint 70 well known in the art. Standard inthe art type quick release joint, final cutting nozzle assembly and cokeremoval technique are illustrated in FIGS. 6 and 7 of the aforementioned"Hydraulic Decoking paper by .Iagodzinski et al. In such standard in theart nozzle arrangement and/or removal technique using same, the jetnozzles must of necessity always be located very close to the drill stemfor accomodation in the pilot hole with the consequence that, for anygiven horizontal layer of coke removed, the distance between the cokebeing acted upon and the ends of the jet nozzles changes as the coke isprogressively removed radially commencing at the perimeter of the pilothole and proceeding toward the container wall.

In the present invention, rather than proceeding in the foregoing mannerto remove the main body of the coke after first cutting the centralpilot hole, instead a special final cutter assembly 11, illustratedschematically in FIGS. 2-6, and in detail in FIGS. 7-12, is thenemployed in the next sequence of steps. As is the case with finalcutting nozzles as employed in the prior art, cutter assembly 11 isoperatively mounted and coupled to a drill stem 7 but in the presentinvention this is accomplished by novel mechanical and hydraulic linkingmeans, indicated schematically at 12, between water nozzles 13 and thecentral drill stem 7.

FIG. 2 illustrates the cutter assembly mechanism of the presentinvention in a position in the coke container approximately midwayduring the first vertical cutting after the cutting of the pilot hole.The nozzles 13 are about halfway down the container. This typifies theirposition when the cutting action has taken place for some time and afterthe central drill stem 7 has been periodically lowered several feet inthe container. It will be noted that the jet nozzles 13 are maintainedin a substantially, but not exactly, vertical direction so that the jetstreams from same are also directed in a substantially verticaldirection against the coke, starting at the top surface of the coke inthe container and finishing at the bottom thereof. The distance of thejet stream between the nozzles 13 and the surface 14 of the coke beingcut may vary depending on the hardness of the coke and the rate oflowering the drill stem but will be substantially constant for a givenset of condi tions as the drill stem is lowered in the container. Thejet nozzles are directed at an angle slightly outward (radially) againstthe surface of the coke in order to pro vide a positive workingclearance for the cutter assembly in the hole generated by the cuttingaction. It is thus seen that, when the step illustrated in FIG. 2 iscompleted, the diameter of the central hole in the container issubstantially increased or enlarged as compared to the diameter of theinitial pilot hole I. For preferred results in the present invention,the diameter of the central hole is progressively changed by about 2 toabout 4 feet for each complete vertical cutting employed in the removalof the coke. (In the step illustrated in FIG. 2, the central pilot hole1 was 2 /2 feet in diameter and the enlarged hole 15 was 5'1: feet indiameter).

Upon completion of the step of FIG. 2, the drill stem 7 was raised inthe container and the setting of the cutter assembly 11 was changed byadjusting or altering the positioning of the linking means 12 in orderto increase the diameter of the hole being cut in the container, asillustrated in FIG. 3. More will be said later on when describing FIGS.7-12 so as to what was done in order to make this change, it sufficingfor the present to state that the change can be effected from outsidethe container and that after the change, the water nozzles I3 are stillin a substantially vertical direction. It was thus possible to carry outthe cutting step illustrated schematically in FIG. 3 in substantiallythe same manner as the cutting step of FIG. 2, with the jet nozzles l3and jet streams directed in a substantially vertical direction, but withthe cutting step substantially enlarging the diameter of the centralhole in the container changing it from the diameter of hole 15 to thediameter of hole 16. It will be noted, however, that despite theincreased diameter of the hole and thus the increased distance of theinner wall of the coke being acted upon from the central drill stem, thedistance from the jet nozzles 13 to the coke ledge 14 being acted uponis substantially the same in the step of FIG. 3 as it was the step ofFIG. 2. Because of this, the efficiencies of the water quantities andwater pressures used were maximized, it being appreciated that thenearer the nozzles 13 are to the coke ledge, the less the waterquantities and pressures required are in the order to effect equivalentcoke removal results as compared to the technique of the prior art. Alsosuch reduced water quantities and pressures result in process economiesbecause of less water usage, increased nozzle and pump life and reducedpump maintenance. It will also be noted that in both the steps of FIGS.2 and 3 the distance that the coke *eroded from the ledge 14 has totravel in order to reach the central pilot hole is relatively minimal.In the step of FIG. 3. the diameter of the central hole was changed fromfeet at to a diameter of 9%. feet at 16. The removal step such asillustrated in FIG. 3 is repeated any desired number of times. each timeresulting in an increasing diameter cylindrical void as shown in FIG. 4,the number of times typically depending upon the size coke desired andalso the diameter ot'the container being emptied, the diameter of thecentral hole in the container each time typi cally increasing by fromabout 2 to about 4 feet.

Typically and preferably the least vertical cutting will be carried outin such a manner as illustrated in FIG. 4 leaving a "tube" 17 ofthe cokearound the wall of the container, which tube is then removed in a manneras illustrated in FIG. 5. In a less preferred embodiment the last suchvertical cutting may also remove the tube of coke from the wall of thecontainer, as illustrated in FIG. 6.

Eventually, the diameter of the central hole is increased to a pointwhere the coke remaining in the container is substantially in the shapeof a hollow tube or annulus 17 with a wall thickness which typically maybe from 2 to 3 feet. Because this wall thickness is around thecircumference of the container, the volume of the CUkc remaining in thecontainer is still very substantial. Because it is difficult to removethis coke in a controllablc manner (huge portions or sections of thecoke may fall away from the container wall at once) and also because ofpossible damage to the bottom of the con taincr anchor to railroad carsbeneath the container. and/or of overloading of same, it is preferableto carry out the final cutting in a manner as illustrated in FIG. 5rather than in the manner as illustrated in FIG. 6. (This decision isalso affected by the final wall thick ness of the coke remaining in thecontainer). In the re moval step illustrated in FIG. 5, the coke isremoved by directing the water nozzles 13 in a substantially hori-Zontal direction. (apparatus features which make this possible aredescribed hereinafter) whereas in the step illustrated in FlG. 6, thecoke is removed by directing the water nozzles at the coke in asubstantially vertical direction just as it is in the steps illustratedin FIGS. 2, 3 and 4.

It will be noted from the foregoing. however, that if and when ahorizontal cutting ofthe coke is resorted to in the present invention asin FIG. 5, the nozzles 13 are quite distant from the axis of the drillstem 7 and close to the surface of the coke being acted upon. It willalso be noted that the distance that the removed coke has to travel inorder to reach the removal hole in the container is minimal. Therefore,if this variation of the invention is resorted to. the advantages ofefficient utilization of water pressure and water flows and minimumgrinding of the coke are still obtained, despite the fact that the jetstreams are in a substantially horizontal condition rather than in asubstantially vertical condition.

Referring now to FIG. 7, the drill stem is shown at 7. The final cutterassembly, indicated generally at II, includes drill stem extension 110.linking means indicated generally at 12, nozzles 13 and such otherfeatures as are necessary to carry out the present invention. The cutterassembly is connected or operatively mounted and coupled. mechanicallyand hydraulically. to the drill stem at the quick release joint or quickdisconnect coupling 7a. The cutter assembly is made up of several partsboth mechanical and hydraulic, which are operatively linked to the drillstem so that the jet nozzles 13 of the valve assembly can be providedwith water and also so that the jet nozzles can be lowered in thecontainer and also extended radially to carry out the hydraulic cuttingsof the coke in the manner previously described. These include a branchedswivel connector 18 connected to drill stem extension Ila, which swivelconnector is capable of mechanically supporting the remaining partsofthe cutting apparatus and of also serving as a part of the conduitsystem for the water from 11a to the nozzles 1.3. The remainder ofthewater conduit system is made up of swivel joint 19, water line 20 andswivel joint 21 on the righy side of FIG. 7 and their counterparts 19a,20a and 210 on the left side of FIG. 7. The high-pressure swivel joints19, 19a, 21 and 21a are well known in the hydraulics art. For example,swivel joints which will satisfactorily carry out the desired functionsin the present invention are commercially provided by the FMCCorporation, Chiksan Divi sion, Brea, Calif, Joint Style No. 40 beingparticularly suitable. Conventional couplings 22 are used throughout thesystem to connect the various swivel joints, water lines and nozzles.

Lever arms 23, 24, 25 and 26 provide part of the mechanical means forcontrolling the radial positioning of the nozzle 23 on one side of thecutter and lever arms 23a, 24a., 25a and 260 do the same on the otherside of the cutter. The radial positioning of these arms is controlledby motor 27, drive screw 28 and drive nut 29. Motor 27 is typically ofthe hydraulic or pneumatic type and is illustrated as being attached toconnector I8 by mechanical support means 30. The positioning of thissupport means 30 may be varied which in turn can be used as a controlfor the vertical positioning of the hydraulic motor and consequently. tosome degree. the radial extension of the nozzles 13. The dimensions orlengths ofthe various lever arms and water lines can be varied in orderto provide for the desired amount of the radial extension of thenozzles. The amount of radial extension of the nozzles required ordesired will, of course, depend upon the diameter of the container whichis to be decoked. Control 31 (eg. a valve) is operatively connected tomotor 27. Opening and closing this valve thus controls the running ofmotor 27 which in turn determines the turning and adjustment of drivescrew 28 in drive nut 29. The threading of drive screw 28 into andthrough nut 29 causes the vertical raising of the drive nut and theradial extending of the lever arms and consequently of the nozzles 13.Maximum lifting of drive nut 29 results in maximum radial extension ofthe cutter system, during which the angle at which lever arms 23 and 23aintersect at the drive nut 29 increases substantially and causes leverarms 24 and 24a to go from a vertical position to a horizontal position.(This final positioning of the rigid arms is shown in FIG. 7 by the useof the dotted lines). In this transition the drive nut 29 acts on thelinks or lever arms 23 and 230 which because of their linkage to arms 24and 24a at points B and 8. cause arms 24 and 24a to rotate about movablepivot points B and B,, and fixed pivot points C and C respectively, inturn causing the nozzles 13 to swing radially outward. When arms 24 and24a thus rotate about points C and C the water lines 20 and 20a rotateabout pivot points E and E at the swivel joints l9 and 19a. Lever arms25 and 250 complete the forming of parallelograms C E H G and C E H Gthe line C E always remaining parallel to the line G H, as is true alsoof the line C E to the line G H Thus at any angle of rotation of the arm24 about the pivot C or of the arm 240 about C., the direction of thejet nozzles 13 relative to the axis of the drill stem remains constant.

Valve 32 is used in the operation of hydraulic cylinders used inconnection with control arms employed in the embodiment of the inventiondescribed in connection with FIG. 5, which embodiment is also describedin more detail hereinafter in connection with FIGS. -12.

Drill stem extension 110, shown in cut-away view in, FIG. 7, may be ofvariable length. but must be long enough so that when drill stem 7 israised after a complete vertical cutting, the valve 31 will be abovecontainer opening 4 so that it may be opened and closed to operate themotor, so that the next desired radial po sitioning of the nozzles canbe effectuated. The same consideration applies to the placement andoperation of valve 32 is the embodiment of FIGS. 10-12 is to beemployed. Also, preferably the drive nut 29 will be coupled to anindicator device so that when the drill stem is raised a reading orobservation coordinated to the extent of vertical movement of the drivenut will inform the operator of the amount of radial extension of thenozzles 13. He will thus be able to accurately adjust the cuttingdiameter for each vertical pass up to and including the final cut.

FIGS. 8 and 9, which are top and side views of the apparatus, are setforth in order to complete the illustration from different perspectiveof how the various parts of the apparatus are assembled. The descriptionand function of the various numbered parts of these figures are clearfrom the detailed description of these same parts and their functions inconnection with the earlier discussion of FIG. 7.

FIGS. 10-12 also illustrate several parts of the apparatus which havealready been previously described and, therefore, such correspondinglynumbered parts require no further discussion. However, in these figures,lever arm 24 has been partially replaced by parts numbered 35, 36, 37and 38. In FIGS. 7, 8 and 9, lever arm 24 is fixed in its lengththroughout the entire decoking operation, with the result that lever arm25 stays at the same relative angle a (with respect to horizontal)throughout the various decoking steps. However, in FIGS. 10-12, leverarm 24 is partially replaced by hydraulic cylinder 36, hydraulicallyactuated pushrod 37, connecting arm 35 and coupling means 38. Theopening and closing of valve 32 actuates hydraulic cylinder 36 with theresult that the cylinder piston (not shown) controllably extendspush-rod 37 from said cylinder. Thus, fixed-in-length lever arm 24 ispartially replaced by a variable length linkage which can be employed tocontrollably change the angle (a) which lever arm 25 makes withhorizontal (changing from obtuse to acute). thus also changing the angleof the nozzle 13 from a substantially vertical direction to asubstantially horizontal direction in order to carry out the removalstep as illustrated in FIG. 5.

While the foregoing figures show one type of mechanical and hydrauliclinkage means for extending the cutting nozzles, and also altering theirdirection for the final cut, it should be readily appreciated that manyother mechanisms can be used to accomplish these same purposes.

It should also be appreciated that since many coke drums have projectingthermocouple wells in the drum, the extension equipment will be sodesigned as to prevent mechanical contact of the cutters with suchequipment.

The modification of the mechanism illustrated in FIGS. 10-12 permitsrotation of the cutter head and elevation of the nozzles to thehorizontal or near horizontal to make a final cleaning of the coke drumwalls. Since the extension means prevents raising the cutting head tothe very top of the drum, occasionally or each time the drill stem israised upon the completion of a cylindrical cutting, the heads can atthat moment be temporarily rotated to horizontal (or even abovehorizontal) by operating valve 32 to clean the upper part of the drumbefore returning the nozzles to their substantially vertical anddownward direction and carrying out the next vertical cylindricalcutting.

From the foregoing description, it is thus readily apparent that theprocess and apparatus of the present invention result in severaladvantages including the following chief advantages:

a. Significantly fewer coke fines are produced since little or nogrinding of dislodged lumps occurs in the cutting operation;

b. No real limit is imposed on the drum diameter by the cuttingoperation;

0. Significantly lower water pressures and volumes may be used in orderto achieve the cutting rates attained by present or prior art cuttingsystems;

(I. With the same water flow rates and pressures as employed in theprior art, the rate of coke removal is substantially increased;

e. The total volume of water handled is substantially decreased andthere is, therefore, increased nozzle and pump life and reduced pumpmaintenance;

f. All dislodged coke is immediately dropped out of the drum and doesnot interfere with the cutting process. This is a most important factorin increasing the speed at which the drum is decoked; and

g. Because of reduced decoking time, the system is much better able thanprior art systems to guard or insure against exceeding the maximum timeallowed for the hydraulic decoking operation. (As pointed out in the.Iagodzinski et al article, extension of this time beyond the customary4-5 hours allotted for same upsets the operating cycle and can causereduction of the feedstock charge rates into the coker and consequentloss of productivity and can even lead to shutdowns).

It is to be understood that the invention is not limited to the specificdetails which have been offered merely for illustrative purposes andthat modifications may be made within the scope of the appended claimswithout departing from the spirit of the invention.

I claim:

1. An apparatus used for removing coke from a delayed coking containerby a series of substantially cylindrical and vertical hydraulic cuttingsof the coke after a substantially vertical and central pilot hole isfirst cut through the entire height of the coke in the container, saidremoval means including:

Water nozzles capable of directing water in jet streams in asubstantially vertical and downward direction against the top surface ofthe coke;

a central drill stem, which can be provided with water under pressure,capable of rotation and vertical movement within the container. to whichstem tl'i jet nozzles are operatively mounted and coupled: and

mechanical and hydraulic linking means between the water nozzles and thecentral drill stem for radially extending the cutting action of the jetstreams while simultaneously maintaining the jet nozzles in about thesame substantially vertical direction. thus enabling each subsequentcylindrical hydraulic cutting in the series to enlarge the diameter ofthe central hole in the container by the total radial movement of thenozzles between each respective cutting in the series;

the vertical and rotary movement of the drill stem.

the radial extension of the linking means. and the hydraulic actionofthe jet streams all thus coacting in the removal of the coke.

2. An apparatus according to claim 1 wherein the linking means forradially extending the cutting action of the jet streams are actuated toa change of position by a motor. a screw driven by said motor. and adrive nut into which said screw is threaded. said drive nut beingmechanically coupled to lever arms of said linking means and causingsaid lever arms to radially extend when said drive screw is furtherthreaded into or through said nut. the operation of said motor beingcapable of being controlled from outside the coking container wheneverone of the vertical cuttings in the series is ready to be commenced,

3. In an apparatus used for removing coke from a delayed cokingcontainer after a substantially \ertical and central pilot hole is firstcut through the entire height of the coke in the container. whichapparatus includes a drill stern which can be provided with water underpressure and which drill stem is capable of rotation and verticalmovement within the container and to which drill stem water nozzlescapable of directing water in jet streams are operatively mounted andcoupled. the improved removal means which include:

Water nozzles capable of directing water in jet streams in asubstantially vertical and downward direction against the top surface ofthe coke. and

mechanical and hydraulic linking means between the water nozzles and thecentral drill stern for radially extending the cutting action of the jetstreams while simultaneously maintaining the jet nozzles in about thesame substantially vertical direction. thus enabling removal of cokefrom the container by a series of substantially cylindrical andvertical. hydraulic cuttings. and thus also enabling each subsequentcylindrical hydraulic cutting in the series to enlarge the diameter ofthe central hole in the container by the total radial movement of thenozzles between each respective cutting in the series.

1. An apparatus used for removing coke from a delayed coking containerby a series of substantially cylindrical and vertical hydraulic cuttingsof the coke after a substantially vertical and central pilot hole isfirst cut through the entire height of the coke in the container, saidremoval means including: Water nozzles capable of directing water in jetstreams in a substantially vertical and downward direction against thetop surface of the coke; a central drill stem, which can be providedwith water under pressure, capable of rotation and vertical movementwithin the container, to which stem the jet nozzles are operativelymounted and coupled; and mechanical and hydraulic linking means betweenthe water nozzles and the central drill stem for radially extending thecutting action of the jet streams while simultaneously maintaining thejet nozzles in about the same substantially vertical direction, thusenabling each subsequent cylindrical hydraulic cutting in the series toenlarge the diameter of the central hole in the container by the totalradial movement of the nozzles between each respective cutting in theseries; the vertical and rotary movement of the drill stem, the radialextension of the linking means, and the hydraulic action of the jetstreams all thus coacting in the removal of the coke.
 2. An apparatusaccording to claim 1 wherein the linking means for radially extendingthe cutting action of the jet streams are actuated to a change ofposition by a motor, a screw driven by said motor, and a drive nut intowhich said screw is threaded, said drive nut being mechanically coupledto lever arms of said linking means and causing said lever arms toradially extend when said drive screw is further threaded into orthrough said nut, the operation of said motor being capable of beingcontrolled from outside the coking container whenever one of thevertical cuttings in the series is ready to be commenced.
 3. In anapparatus used for removing coke from a delayed coking container after asubstantially vertical and central pilot hole is first cut through theentire height of the coke in the container, which apparatus includes adrill stem which can be provided with water under pressure and whichdrill stem is capable of rotation and vertical movement within thecontainer and to which drill stem water nozzles capable of directingwater in jet streams are operatively mounted and coupled, the improvedremoval means which include: Water nozzles capable of directing water injet streams in a substantially vertical and downward direction againstthe top surface of the coke; and mechanical and hydraulic linking meansbetween the water nozzles and the central drill stem for radiallyextending the cutting action of the jet streams while simultaneouslymaintaining the jet nozzles in about the same substantially verticaldirection, thus enabling removal of coke from the container by a seriesof substantially cylindrical and vertical, hydraulic cuttings, and thusalso enabling each subsequent cylindrical hydraulic cutting in theseries to enlarge the diameter of the central hole in the container bythe total radial movement of the nozzles between each respective cuttingin the series.